Tailoring magnetic anisotropy gradients by ion bombardment for domain wall positioning in magnetic multilayers with perpendicular anisotropy

• Published in: Nanoscale research letters Vol. 9; no. 1; p. 395
• Main Authors: Matczak, Michał, Szymański, Bogdan, Kuświk, Piotr, Urbaniak, Maciej, Stobiecki, Feliks, Kurant, Zbigniew, Maziewski, Andrzej, Lengemann, Daniel, Ehresmann, Arno
• Format: Journal Article
• Language: English
• Published: New York Springer New York 13-08-2014; Springer Nature B.V; BioMed Central Ltd; Springer
• Subjects: Chemistry and Materials Science; EMN Meeting; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Perpendicular magnetic anisotropy; Ion bombardment; Domain walls
• ISSN: 1931-7573; 1556-276X; 1556-276X
• DOI: 10.1186/1556-276X-9-395

Graded anisotropy magnetic materials possess a coercive field changing laterally with position. A simple fabrication procedure to produce such an anisotropy gradient in a polycrystalline Au/Co layer system without lateral thickness variation and with perpendicular magnetic anisotropy, prototypical for a large variety of thin film systems, is shown. The procedure uses light-ion bombardment without the use of a mask. Magnetization reversal in this polycrystalline layer system takes place by unidirectional movement of a single domain wall only in regions with larger anisotropies and anisotropy gradients. In this anisotropy/anisotropy gradient regime, the domain wall is oriented perpendicular to the coercive field gradient, and it can be positioned along the gradient by an appropriate magnetic field pulse. For smaller anisotropies/anisotropy gradients, the natural anisotropy fluctuations of the polycrystalline layer system induce magnetization reversal dominated by domain nucleation.
PACS
75.30.Gw; 75.70.Cn; 75.60.Ch